A centraliser (10) for use in centralising tubing (12) in a bore (W) comprises a first end collar (14), a second end collar (16) and a number of elongate strut members (18). The strut members (18) are interposed between the first end collar (14) and the second end collar (16) and are circumferentially arranged and spaced around the first end collar (14) and second end collar (16). The strut member (18) have a first end portion (20), a second end portion (22), an intermediate portion (24) and angled wing portions (26) which extend from the intermediate portion (24).

A centralizer for use in a wellbore includes a body for disposing around a periphery of a downhole tubular. The body has a plurality of bow springs biased toward an expanded position and a pair of end rings connecting the bow springs. The centralizer further includes an indentation or row of indentation segments formed in a surface of and along each bow spring. The indentations or indentation segments are operable to reduce a stiffness of the centralizer as the bow springs move from the expanded position to a restricted position.

The present disclosure provides methods for bonding a first downhole tool to a borehole tubular, which include applying solder particles, each particle having an outer shell and a core of liquid metal, to at least one of a surface of the first downhole tool or a surface of the borehole tubular. The methods may also include rupturing the shells of the solder particles to release the liquid metal cores. The methods may further include bonding the first downhole tool to the borehole tubular by allowing the released liquid metal core to solidify.

A stop collar for mounting to a downhole tubular includes: a cylindrical housing having a threaded inner surface and a tapered inner surface; a compressible slip ring having teeth formed in an inner surface thereof and a pair of tapered outer surfaces; a solid cam ring having a tapered inner surface; and a cylindrical bolt having a threaded outer surface. A natural outer diameter of each ring is greater than a minor diameter of the threaded surfaces. Screwing the threaded surfaces of the housing and the bolt is operable to drive the tapered surfaces together, thereby compressing the slip ring such that the teeth engage a periphery of the tubular.

A method of cementing a casing in a wellbore extending from an Earth's surface into a subsurface includes providing a tube having a bi-frustoconical shape. The bi-frustoconical shape is defined by an upper tube part having an inverted frustoconical shape, a lower tube part having a frustoconical shape, and a waist intermediate between the upper tube part and the lower tube part. The tube is positioned in an annulus formed between the casing and a wall of the wellbore from a surface opening of the annulus. The tube is urged in a direction down the annulus and along the casing until the tube lands on a collar radially projecting from an outer surface of the casing into the annulus.

Systems and methods include a computer-implemented method for predicting fluid holdups along the borehole or the pipe on surface and to perform fluid typing and fluid properties characterization. Acoustic waves are transmitted by an array of acoustic wave transducers. Each transducer is configured to transmit acoustic waves at a different frequency. The acoustic waves are received by an array of acoustic wave receivers fixed on the bow centralizer on the tool used in the borehole. Each receiver is configured to receive only the given frequency of a given transducer, forming a receiver-transducer pair for the given frequency. Acoustic speeds measured at each given frequency and analyzed. A model is generated based on the analyzing. The model is configured to predict fluid holdups across the borehole and to perform fluid typing and fluid properties characterization in one phase, two phase, and three phase applications of gas, oil, and water.

A flexible collet on a subterranean tool has sacrificial soft components to protect seal bores through which the collets have to compress to get through. The sacrificial components can be replaced when the tool is removed to the surface. In one embodiment, threaded fasteners are used alone or with washers for height adjustment such that the heads of the fasteners which are softer than the seal bore material ride on the seal bore and take the wear. The tool can ultimately be used to latch into shifting sleeves to move such sleeves to open or close wall ports. Alternatively axial ridges with beveled profile ends can be used or rolling members such as wheels or balls can be used to keep sharp edges off the seal bore. EDM method can be used to create multiple fingers with an axial ridge profile and rounded end transitions.

Embodiments described herein provide a multi-diameter thrust device that includes one or more thrust cups. Each thrust cup of the one or more thrust cups includes a first axial end hub disposed at a first axial end of the thrust cup; a second axial end hub disposed at a second axial end of the thrust cup; and a plurality of bowsprings. Each bowspring of the plurality of bowsprings includes a first axial end portion coupled to the first axial end hub and a second axial end portion coupled to the second axial end hub. The plurality of bowsprings are disposed circumferentially about a central axis of the multi-diameter thrust device.

A centralizer with low friction buttons comprising a plurality of collars including a first collar and a second collar; a plurality of bow springs, each bow spring having a first end and a second end; and a plurality of low friction buttons. The plurality of bow springs extend between the first and second collar such that the first and second end of each bow spring is connected to the first and second collar respectively; the plurality of low friction buttons are mounted on the bow springs such that they act as the only point of contact between the centralizer and borehole during movement of the pipe casing while getting it to the total depth during drilling operation, said buttons being of the type whose coefficient of friction is lesser than the rest of the body of the centralizer.

The present disclosure provides a bow-spring centralizer by using thinner bows of advanced alloys and thermal conditioning that can reduce the thickness of the bows compared to traditional bows, and yet provide sufficient restoring force after compression in a tight annulus with little radial thickness. The present disclosure also provides a specially shaped centralizer bow with cross sections that can reduce running force, increase stiffness and strength, and/or still maintain a sufficient restoring force.